Seven square mile ice chunk breaks off

Canada’s largest remaining ice shelf looses piece; shelf crack found in 2002; Ellesmere Island used to be ringed by an ice shelf

The Associated Press

Officials said July 29 a chunk of ice about seven square miles in size has broken off Canada’s largest remaining ice shelf.

Trent University researcher Derek Mueller said he wouldn’t surprise him if even more ice broke off this summer from the Ward Hunt Ice Shelf, a vast frozen plain off the north coast of Ellesmere Island in Canada’s far north.

In a development consistent with climate change theories, an enormous icy plain broke free sometime the week ending July 25 and began slowly drifting into the Arctic Ocean. The piece had been a part of the shelf for 3,000 years.

A crack in the shelf was first spotted in 2002. Last spring, a patrol of Canadian Rangers found the weakness had spread into an extensive network of cracks, some 40 meters wide and 11 miles long.

Formed by accumulating snow and freezing meltwater, ice shelves are large platforms of thick, ancient sea ice that float on the ocean’s surface. Ellesmere Island was once entirely ringed by a single enormous ice shelf that broke up in the early 1900s. At 170 square miles in size and 40 meters thick, the Ward Hunt shelf is the largest of those remnants — seven times the size of the Ayles Ice Shelf chunk that broke off in 2005 from Ellesmere’s western coast.

Despite a period of stability in the 1980s, the Ward Hunt shelf and its characteristic corrugated surface has been steadily declining since the 1930s, said Mueller. Its southern edge has lost seven square miles over the last six years.

Mueller is careful not to blame the Ward Hunt breakup specifically on climate change, but said it is consistent with the theory.

“We’re in a different climate now,” he said. “It’s not conducive to regrowing them. It’s a one-way process.”

It’s the same all over the Arctic, said Gary Stern, co-leader of a major international research program on sea ice. Speaking from the Coast Guard icebreaker Amundsen in Canada’s north, Stern said the Ward Hunt breakup is related to what he’s not seeing thousands of miles -- ice. Plans to set up an ice camp last February had to be abandoned when usually dependable ice didn’t form for the second year in a row.

“Things are happening fast and they’re going to continue to happen fast,” Stern said.

Many scientists believe that the Arctic will have ice-free summers by 2013 instead of 2030 as predicted by the International Panel on Climate Change.